Method for protecting plants from powdery mildew fungus and fungicidal composition to be used therefor

ABSTRACT

A METHOD FOR PROTECTING PLANTS FROM POWDERY MILDEW FUNGUS BY APPLYING TO SAID PLANTS AT LEAST ONE AMIDINE COMPOUNDS SELECTED FROM THE CLASSS CONSISTING OF COMPOUNDS REPRESENTED BY THE FORMULA   R1-NHC(=NH)-R2   WHEREIN R2 REPRESENTS AN ALKYL GROUP AND R1 REPRESENTS A GROUP SELECTED FRON THE GROUP CONSISTING OF PHENYL AND NAPHTHYL GROUPS HAVING FROM 0 TO 2 SUBSTITUENTS SELECTED FROM THE CONSISTING OF HALOGEN ATOMS, ALKYL, NITRO AND ALKOXY GROUPS AND ADDITION SALTS OF SAID COMPOUNDS WITH ACIDS. ALSO CONTEMPLATED ARE FUNGICIDAL COMPOSITIONS FOR THE CONTROL OF POWDERY MILDEW FUNGUS CONTAINING THE ABOVE-MENTIONED COMPOUNDS AS THE ACTIVE INGREDIENTS.

United States Patent 015cc 3,754,093 METHOD FOR PROTECTING PLANTS FROMPOWDERY MILDEW FUNGUS AND FUN- GICIDAL COMPOSITION TO BE USED THEREFORKenji Shigezane, Mie, Ryuzo Nishiyarna, Kyoto, Kanichi Fujikawa, andKiroyuki Mori, Shiga, Japan, assignors to Ishihara Sangyo Kaisha, Ltd.,Osaka. Japan N Drawing. Filed Apr. 28, 1970, Ser. No. 32,761 Int. Cl.A01n 9/20 US. Cl. 424-326 27 Claims ABSTRACT OF THE DISCLOSURE A methodfor protecting plants from powdery mildew fungus by applying to saidplants at least one amidine compound selected from the class consistingof compounds represented by the formula wherein R represents an alkylgroup and R represents a group selected from the group consisting ofphenyl and naphthyl groups having from O to 2 substituents selected fromthe group consisting of halogen atoms, alkyl, nitro and alkoxy groupsand addition salts of said compounds with acids. Also contemplated arefungicidal compositions for the control of powdery mildew funguscontaining the above-mentioned compounds as the active ingredients.

BACKGROUND OF THE INVENTION (1) Field of the invention The presentinvention relates to a method for protecting plants from powdery mildewfungus by applying an amidine compound and to fungicidal compositionscontaining such amidine compounds.

(2) Description of prior art Powdery mildew fungus causes serious damageto cultivated vegetables, such as cucumbers, melons, strawberrys,eggplants, and green peppers; cereals such as wheat; fruit, such asapples and pears; flowering plants, such as roses and chrysanthemums;and pasture plants, such as clover and Italian ryegrass.

This fungus is so vital that, even if the white spores thereof arekilled by breaking, it soon resuscitates and is therefore extremelydifficult to eradicate by means of fungicidal chemicals. The completeprotection of plants from powdery mildew fungus requires destruction ofthe fungus both inside and outside of the host tissues. The control ofpowdery mildew fungus has been found to be extremely difiicult.

In fact, many conventional fungicides exert insuflicient controllingeffects on powdery mildew and, in particular, conventional fungicideshave proved insufiicient for curative control on plants already infectedby the fungus. If such fungicides are applied so as to obtain fairlysatisfactory control effects, phytotoxicity toward cultivated plantswould be likely.

An object of the present invention is to provide a method of protectingcultivated plants effectively from powderly mildew fungus by applyingchemicals which are not phytotoxic and cause substantially no damage tothe plants.

Another object of this invention is to provide novel fungicidalcompositions capable of protecting cultivated plants from powdery mildewfungus without causing any substantial damage to the cultivated plants.

Other objects and advantages of this invention will become apparent fromthe following description.

SUMMARY OF THE INVENTION According to the present invention there isprovided a method of protecting plants from powdery mildew fun-3,754,093 Patented Aug. 21, 1973 gus by applying at least one amidinecompound selected from the group consisting of compounds represented bythe formula wherein R represents an alkyl group and R represents a groupselected from the group consisting of phenyl and naphthyl groups havingfrom O to 2 substituents selected from the group consisting of halo,alkyl, nitro, and alkoxy and acid-addition sals of said compounds, saidcompounds being applied to the locus of cultivation of the plants in aconcentration suflicient to exert fungicidal action on powdery mildewfungus.

Also provided according to the present invention invention arefungicidal compositions containing the aforesaid amidine compounds forcontrol of powdery mildew fungus.

DETAILED DESCRIPTION OF THE INVENTION The preparation of the aforesaidamidine compounds will now be described below with reference to thepreparation of N-(Z-methylphenyl) propionamidine, its oxalate andN-(2,4-dimethylphenyl)acetamidine and its oxalate. Other amidinecompounds represented by the aforesaid general formula may be preparedaccording to procedures such as that described below.

PREPARATION OF N- (Z-METHYLPHENYL) PRO- PIONAMIDINE AND ITS OXALATE In aflask, 10.7 g. of o-toluidine was mixed with 5.5 g. of propionitrileand, after adding 13 g. of powdered anhydrous aluminum chloride whilecooling the mixture with water from the outside of the flask, theresultant mixture was heated to 140 C. on an oil bath for 3 hours. Waterwas added to the reaction mixture. An aqueous solution of the productwas rendered alkaline with sodium hydroxide and extracted withchloroform. The chloroform was removed from the extract thus obtained,and a saturated acetone solution of oxalic acid was added to theresidue. The crystalline precipitate was filtered and thenrecrystallized fromaqueous acetone to provide 7.6 g. ofN-(Z-methylphenyl)propioamidine oxalate crystals having a melting pointof 164-166" C.

The oxalate prepared above was then dissolved in water and the solutionwas rendered alkaline with aqueous sodium hydroxide solution. Afterextracting the product with chloroform, the extract was dehydrate withanhydrous sodium sulfate and the chloroform was removed from thedehydrated product to provide 4.0 g. of oilyN-(Z-methylphenyl)propionamidine.

PREPARATION OF N-(2,4-DIMETHYLPHENYL) ACETAMIDINE AND ITS OXALATE In aflask, 12.1 g. of 2,4-dimethylaniline was mixed with 4.2 g. ofacetonitrile and, after adding 13 g. of powdered anhydrous aluminumchloride while cooling the mixture was heated to C. on an oil bath for 5hours. Treating the reaction product in the same way as described above,8.4 g. of N-(2,4-dimethylphenyl)acetamidine oxalate crystals having amelting point of 199-210 C. was obtained. From the oxalate, 2.5 g. ofoil N-(2,4- dimethylphenyl)acetamidine was obtained, as above.

EXAMPLE 1 Soil was charged into unglazed pots, each having a diameter of9 cm. and five seeds of cucumber were sowed in each pot. When theircotyledons were completely developed and the first leaves began tosprout, powdery mildew fungus (Sphaerotheca fuliginea) was inoculatedupon the cotyledons. Three days after the inoculation, 10 ml. of thefungicidal composition which had just been prepared as shown below wasuniformly sprayed onto each pot. Ten to fourteen days after thespraying, the

degree of the fungus infection was visually observed. The results areshown in Table 1. Non-treated in the table (test number 82) refers to alot which was not treated with the fungicidal composition. Each of thefungicidal compositions used in tests 1-27 and 56-81 was prepared bymixing together 50 parts by weight of the fungicidal active ingredientof this invention, 40 parts by weight of xylol, and 10 parts by weightof polyoxyethylene glycol to provide an emulsifiable concentrate anddiluting it with water to the indicated concentration. The fungicidalcompositions employed in tests 28-55 were prepared by diluting therespective fungicidal active ingredients directly with water to theindicated concentration.

The results of the fungus infections were rated in Table 1 on a scale offrom to 4 as follows:

0: No infection 1: Slightly infected 2: Moderately infected 3: Severelyinfected 4: Very severely infected In the following, the activeingredient is N-R-propionamide wherein R is as indicated.

TABLE la Degree of fungus infection 1,000 500 250 p.p.m. p.p.m. p.p.m

Melting point Test No. R

9 3-methoxyphenyl. 10- emethoxyphenyL" 11- 2ethoxyphenyl lwtltwwuomremember-wow 2,4-dimethylphenyl 2,5-dimethylphenyl 2,6-dimethylphenylSA-dimethylphenyl l-naphthyl 2-naphthyl ocooooocoooooooccccaccoo cooozeoo HHpPlOl-H 1 Liquid indicates that the compound is liquid at roomtemperature In the following, the active ingredient isN-R-propionamidine oxalate, wherein R is as indicated.

38- 2-methoxyphenyl 3-methoxyphenyl.

40- 4-methyoxphenyl 41- 2-ethoxyphenyl,

caseooaoooocoocaoccoeooooocc I- NwOOO HNNOr- HOJwHWt- HHQOOHOO FWNI- OON'NWIOOHHOJWWOJHHNHQONQNl- 42- B-ethoxyphenyl 4-ethoxyphenyl2,3-diehlorophen 2 -dichloropheny 2,5-diehloropheny 2 fi-diehloropheny3,4-d1ehloroph nyL- 3,5-dichioropheny1 176-178. 5 50-2,3-dimethylphenyl- 182-182. 6 51, 2,4-dimethylphenyl. 6-168 52-2,5-dimethylphenyl. 161. 5-163 53- 2,6-dimethylphenyl. 1. 181-183 54-aA-dimethylphenyl. 165.5-167 55- l-naphthyl 219-221 In the following,the active ingredient is N-R-acetamidine, wherein R is as indicated.

TABLE 10 Degree of fungus infection Test Melting 1, 000 500 250 N o. Rpoint p.p.m. p.p.m. p.p.m

56. Phenyl Liquid Liquid Liquid 113-114 2-methylpheny 3-methylphenyl.4-methylpheny 2-uitrophenyl- 6t. 3-niirophenyl- 65- 4-nitrophenyi. 66-2-rnethoxyphenyL. 67- 3-methoxyphenyL. 68- 4-methoxyphenyL- 69-2-ethoxyphenyi. 70- S-ethoxyphenyL- 71- 4-etl1oxyphenyl 72-2,3-diehlor0phenyl 73- 2,4-diehloropheny1. 74. 1 2,5-diehlorophenyl.-.75. 3,5-dichlorophenyl--..- 76- 2,3-dlmethylphenyl- 77.2,4-dimethylphenyl- 78- 2,5-dimethylphenyL occoccooccwrccccooocoacooo P''OOOoWl-W-OWNHNOJHHHN Co -OOH weep-ovum;-wens-tmewwvmenmwwumwu 79-2,6-dimethylphenyl- Liquid 80- 3,4-dimethylphenyl- Liquid 81- l-naphthylLiquid 82- Non-treated 4 In the tests, the above compositions exhibitedno phytotoxicity toward the cucumber seedlings, either by growthinhibition or injury.

For comparison, the same experiments were repeated using the followingcompounds which are outside the scope of the present invention. Thesecompounds proved either ineffective or injurious to the plants in theconcentration range where the fungicidal active ingredients of thepresent invention showed suflicient control effects on powdery mildewfungus.

The compounds used in the comparison tests wereN,N-dimethyl-N-phenylformamidine, N,N-dirnethyl-N'-(4-chlorophenyl)-formamidine,N,N-dimethy1-N-(3-chlorophenyl)formamidine, N,N-dimethyl-N'(4-methoxyphenyl) formamidine, N,N-dimethyl -N'-(1-naphthyl)formamidine, and N,N-dimethyl-N'-(3,4-dichlorophenyl formamidine. Forexample, N,-N-dimethyl-N-(1-naphthyl) formamidine showed a weakfungicidal effect; N, N-dimethyl-N'-(3,4-dichlorophenyl) formarnidinecaused the death of the sample cucumber seedlings andN,N-dimethyl-N'-(4-chlorophenyl) formamidine inhibited the growth ofcucumber seedlings.

EXAMPLE 2 Three-year-ol-d rose seedlings (Variety Queen Elizabeth) eachfertilized and tended in a customary manner in a deep unglazed pothaving a diameter of 18 cm. were placed in a vinyl resin chamber. Fourrose seedlings were grouped as one lot. The control of powdery mildewfungas (Spizaerothecm pannosa) on the roses was efiected on one lot eachin Tests 1 and 2 and on two lots in Test 3 in Table 2 below. Slightgrowth of powdery mildew fungus was observed on all test roses aboutSeptember 20. An aqueous solution of N-(Z-methylphenyl) propionamidineoxalate of the concentration indicated was uniformly sprayed onto theroses at a rate of 80 ml. per pot by means of a sprayer on September 21,September 28, and October 5, respectively. The growth of the roses wasobserved on October 9 and the number of diseased (powderymildew-infected) and healthy leaves observed. The results are shown inTable 2, in which the non-treated lot is a lot which was not treatedwith any chemical.

TABLE 2 Number of Concentration Leaves Healthy Diseased Test No. Testlot (p.p.m.) checked leaves leaves 1 Treated 500 668 660 8 2 do 250 527500 27 3 Non-treated 281 51 No phytotoxicity toward the roses wasobserved.

EXAMPLE 3 Seedlings of cucumber were transplanted on July 23 and powderymildew fungus (Sphaerotheca fuliginea) was controlled. A fungicidalcomposition prepared as shown ylphenylacetamidine,dimethylphenylacetamidine, monochlorophenylactamidine,phenylpropionamidine, monomethylphenylpropionamidine,dimethylphenylpropionamidine, monochlorophenylpropionamidine, and thesalts thereof, each demonstrate excellent results.

b low as sprayed on ten cucumber plants (one plant 5 Among thehalogen-substituted phenylamidine comhad ten leaves) y means of a p y011 August pounds included within the scope of the above formula, gust24, September 3 and September 14 Soon after the the bromineorfluorine-substituted compounds demon- Pfepafafion thereofon August 29,September 16 and strate good results only slightly below those of thechlo- October 4, the number of the diseased leaves was obi b tit d ndserved and the percentage of diseased leaves as compared A t lk l groupcomprising 2 i the f id to the total of 200 leaves was calculated. Thesepercentl f l lower lk l ro tho e having 1 6 carbon ages are shown inTable 3 as the Ratio of Diseased t such as th l, ethyl, n-prop l,isoropyl, sec- Leaves. The non-treated lot in the table is a lot nottreated but l, -butyl, ter-butyl, phenyl, and hexyl groupsdemonwithafungicidal chemical. strate better results. The alkoxy groupscomprising R The fungicidal composition used above was prepared whichexhibit better results also include those having 1-6 by mixing 50 partsby weight of N-(2-methylphenyl)pr0- carbon atoms, such as methoxy,ethoxy, propoxy, butoxy, pionamidine, parts by weight of Xylene, and 20parts pentoxy, and hexoxy group. by weight of polyoxyethylene glycol anddiluting the 0f the acid-addition salts of the aforesaid amidineemulsifiable concentrate with water to the indicated con- 20 compounds,the oxalates and hydrochlorides demonstrate centration. better results.

Aug. 29, Sept. 16, Oct. 4, Concentration ratio of ratio of ratio of ofthe active diseased diseased diseased ingredient leaves leaves leavesTest lot (p.p.m.) (percent) (percent) (percent) No phytotoxicity towardsthe cucumber was observed. Concentrations of the active ingredients tobe applied according to the method of this invention vary dependingEXAMPLE4 upon the particular compound and cultivated plant, the Melonseedlings were transplanted to the field and cultiform of the fungicidalcomposition, the manner of applyvated in the ordinary manner. Control ofpowdery mildew ing the fungicidal composition, and the time ofapplicafungus on the melon was effected. On June 24, July 1, and tion,but usually range between 100 and 2,000 p.p.m., July 9, about 250 litersper 10 acres of an aqueous solupreferably ZOO-1,000 p.p.m.Concentrations below 100 tion of N-(2,4-dimethylphenyl)acetamidinehydrochloride p.p.m. provide insuificient fungicidal effects. Atconcenof the indicated concentration, prepared as in Example trationshigher than 2,000 p.p.m., on the other hand, some 2, was sprayed ontothe melon plants. On' September 11, compounds of the present inventionmay cause damage to the number of spots of powdery mildew fungus diseaseon some plants. The rate of application of the fungicidally the melonleaves in each lot was measured. The results active ingredient isusually 20-400 g., preferably 40-100 are showninTable 4. g. per 10 ares.Application rates outside of the above TABLE 4 range result in the sametendencies as mentioned above in the case of the concentration of theactive ingredient. gffg ggggg Egg; The method and the fungicidalcompositions of this inin t sp ts P vention have a curative effect onplants already infected Test lea! by powdery mildew. Conventionalmethods or fungicidal Number compositions have usually proved inadequateto cure alt:33:21:::::i:::-?ii::::::::::: 3% 3:33 ready infected plantsby p y mildew u us. on the 3 Non- 147.5 other hand, the fungicidalcompositions of the present invention can sufficiently protect plantsfrom the invasion No phytotoxicity towards the melon plants was ob-Powdery lljlildfiw fungus Without Phytotoxicity y P served liminaryapplication of the composition to the plants.

The above examples shall not limit the scope of this in- The fungicidalcompositions of this invention y be ventiom In other words, otheramidine compounds rePre. employed 1n the form of dusts, emulslfiableconcentrates, sented by the aforesaid general formula than those illus-Wat er'S1ub1e P mf Powders 9 trated in the above examples possess thesame fungicidal Whlch may prepafed by adlPlxlng afrea1d amldmeactivities as the aforesaid compounds. For example, Fompound Wlth anInert er a if required, an adnaphthylamidine compounds having one or twosubstitl' uents, either the same or different from each other, phentheer used in this inven there Y be ylamidine compounds substitutedsimultaneously by two ment}ned I1Ve11 t19I1a1S011d ar iers such as talc,l caohne, difierent substituents, and addition salts of these com-Zeekllte y dlvlded y {111116.121 P dlatoma' pounds with acids, such asoxalic, sulfuric, hydrochloric, 660115 earth and Starch; hquld dllutmgagents Such as p-toluenesulfonic, acetic and propionic acid, also arewatel} a1h01$,ac6t0ne, zylene, benzene, solvent naphtha satisfactory andisophorone; and gaseous carriers such as mtrogen,

Among these amidine compounds, a phenylamidine carbon dioxide or Freonand the likecompound, a phenylamidine compound substituted by Theabove-mentioned adjuvant includes, for instance, chlorine or a methylgroup, a naphthylamidine comemulsifying dispersants, such as sodiumalkylbenzenesulpound, and a chlorine-substituted naphthylamidinecomfonates; sodium higher alcohol sulfonates; polyoxyethylpounddemonstrate better results. It has been confirmed ene alkyl allylethers; polyoxyethylene glycol alkyl ethers, that of these compounds,phenylacetamidine, monomethcalcium ligninesulfonate, polyvinyl alcoholand the like.

Almost all of the aforesaid amidine compounds are soluble in water to anextent sufficient for the purposes of this invention and therefore, maybe used as an aqueous solution without the use'of an adjuvant. Suchaqueous amidine solutions are particularly convenient for application,as compared with the use of an adjuvant, since formulation before usecan be omitted and there is no fear of contamination of plants with it.Such aqueous amidine solutions may be safely applied to vegetables andflowering plants without fear of hygienic or ornamental contamination.

However, some of the aforesaid amidine compounds are hydrolyzed whenstored for long periods of time in the form of aqueous solutions and donot exert the desired effects of this invention. In such case,otherforms of application maybe used. Alternatively, the fungicidalcompositions prepared in the various forms described above may beapplied directly or after having been diluted just prior to application.

What is claimed is:

1. A method for controlling Sphaerotheca fuliginea on plants whichcomprises:

applying to said infected plants a fungicidally effective amount ofN-(Z-methylphenyl)propionamidine or the acid addition salts thereof.

2. The method of claim 1, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonicacid,acetic acid, and propionic acid. Y

3. The method of claim 1, wherein said compound is sprayed ontosaidfungus.

4. A method for controlling Sphaerotheca fuliginea on plants whichcomprises:

applying to said infected plants a fungicidally effective amount ofN-(3-chlorophenyl)propionamidine or the acid addition salts thereof.

5. The method of claim 4, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and propionic acid.

6. The method of claim 4, wherein said compound is sprayed onto saidfungus.

7. A method for controlling Sphaerotheca fuliginea on plants whichcomprises:

applying to said infected plants a fungicidally effective 7 amount ofN-(3-methylphenyl)acetamidine or the acid addition salts thereof.

8. The method of claim 7, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and propionic acid.

9. The method of claim 7, wherein said compound is sprayed onto saidfungus.

10. A method for controlling Sphaerotheca fuliginea on plants whichcomprises: 1

applying to said infected plants a fungicidally effective amount ofN-(2,3-dichlorophenyl)acetamidine or the acid addition salts thereof.

11. The method of claim 10, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and propionic acid.

12. The method of claim 10, wherein said compound is sprayed onto saidfungus.

13. A method for controlling Sphaerotheca fuliginea on plants whichcomprises; 1

applying to said infected plants a fungicidally effective amount of V v:N- (2,3 dimethylphenyl)propionamidine or the acid addition saltsthereof.

14. The method of claim 13, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and propionic acid. 7

15. The method of claim 13, wherein said compound is sprayed onto saidfungus.

16. A method for controlling Sphaerotheca fuligz'nea on plants whichcomprises:

applying to said infected plants a fungicidally effective amount ofN-(2,4-dimethylphenyl)acetamidine or the acid addition salts thereof.

17. The method of claim 16, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and pro pionic acid.

18. The method of claim 16, wherein said compound is sprayed onto saidfungus.

19. A method for controlling Sphaerotheca fuliginea on plants whichcomprises:

applying to said infected plants a fungicidally effective amount of N(2,4 dimethylphenyl)propionamidine or the acid addition salts thereof.

20. The method of claim 19, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and propionic acid. t

21. The method of claim 19, wherein said compound is sprayed onto saidfungus.

22. A method for controlling Sphaerotheca fuliginea on plants whichcomprises:

applying to said infected plants a fungicidally effective amount ofN-(2,5-din'fethylphenyl)acetamidine or the acid addition salts thereof.

23. The method of claim 22, wherein said acid component of saidacid-addition salts is a member selected from the group consisting ofoxalic acid; sulfuric acid, hydrochloric acid, p'-toluene sulfonic acid,acetic acid, and propionic acid.

24. The method of claim 22, wherein said compound is sprayed onto saidfungus.

25. A method for controlling Sphaerotheca fuliginea on plants whichcomprises:

applying to said infected plants a fungicidally effective amount of N(2,5 dimethylphenyl)propionamidine or the acid addition salts thereof.26. The method of claim 25, wherein said acidcomponent of saidacid-addition salts is a member selected from the group consisting ofoxalic acid, sulfuric acid, hydrochloric acid, p-toluene sulfonic acid,acetic acid, and propionic acid.

27. The method of claim 25, wherein said compound is sprayed onto saidfungus.

References Cited UNITED STATES PATENTS 2,736,748 2/1956 Maliphant et al.260-564 3,206,468 9/ 1965 -Grenda 260'302 FOREIGN PATENTS 485,406 3/1970 Switzerland.

ALBERT T. MEYERS, Primary Examiner A. l, RQBINSON, Assistant Examiner

